Diversity of microcrustacea (Crustacea: Branchiopoda) of Loktak Lake, a Ramsar site, Manipur, India

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B.K. Sharma
S. Sharma

Abstract

Microcrustacea of Loktak Lake (collected during Nov. 2002-Oct. 2004) reveal 57 species and show qualitative dominance of Cladocera (51 species). They indicate monthly richness ranging between 33�plus or minus 6 and 32� plus or minus 6 species, record 51.7-82.3 and 53.6-90.0% community similarities during two years respectively, and follow trimodal annual patterns with peaks during winter. The microcrustaceans (112� plus or minus 17 and 124� plus or minus 13 n/l) form an important quantitative component (45.7� plus or minus 4.9 and 43.3� plus or minus 3.7 %) of zooplankton and show broadly trimodal annual patterns with peak abundance during winter. Cladocera > Copepoda mainly contribute to their quantitative variations. ANOVA registers significant monthly variations of microcrustacea richness and significant annual and monthly variations of their abundance. Richness is positively correlated with dissolved oxygen and is negatively correlated with rainfall, hardness, chloride and total dissolved solids while abundance is negatively correlated with pH only. Multiple regressions indicate higher cumulative effect of 15 abiotic factors on richness and abundance. Our results indicate no definite periodicity of richness and abundance of microcrustacea or their constituent groups during two annual cycles and are characterized by their higher species diversity, higher evenness and lower dominance.

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Author Biographies

B.K. Sharma

specialize in biodiversity and ecology of freshwater zooplankton and have made significant contributions in the fields of their expertise.

S. Sharma

specialize in biodiversity and ecology of freshwater zooplankton and have made significant contributions in the fields of their expertise.